The Horse:Your Guide To Equine Health Care provides monthly equine health care information to horse owners, breeders, veterinarians, barn/farm managers, trainer/riding instructors, and others involved in the hands-on care of the horse.
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40 TheHorse.com THE HORSE September 2017 T he seemingly inconsequential tri- angle of tissue on the bottom of your horse's foot is anything but. In fact, the frog serves a variety of special func- tions that help keep a horse sound. "Paying attention to the frog is one of the most important aspects of keeping a happy, healthy, functioning hoof capsule," says Travis Burns, CJF, TE EE, FWCF, assistant professor of practice and chief of farrier services at Virginia Maryland College of Veterinary Medicine, in Blacks- burg, Virginia. "When the foot starts to have issues, frog health deteriorates," he continues. "Then the problem is self-exacerbating, and the unhealthy frog is prone to thrush and even canker," two anaerobic (able to survive with little to no oxygen) bacterial diseases of the frog and surrounding tissues. In this article we'll explain the frog's many purposes and how to keep it—and, by extension, your horse's hooves in their entirety—healthy. The Frog's Function Here are some of this structure's roles: Shock absorption Bob Bowker, VMD, PhD, professor and head of the Equine Foot Laboratory at Michigan State University, in East Lansing, says the frog is vital for absorbing shock. "Without a good frog, in my opinion, the foot does not function well, and that is why we have so many foot problems." When the foot lands on the ground, the elastic, blood-filled frog helps dissipate some of the force away from the bones and joints, says Amy Rucker, DVM, an ambulatory practitioner in Central Mis- souri who has a special interest in horses' feet. Blood flow The frog plays a major role in pushing blood up out of the hoof. Tia Nelson, DVM, a farrier and veterinar- ian with Valley Veterinary Hospital, in Helena, Montana, explains: "From the knee and hock on down, a big part of what pushes the blood back up to the heart is the venous plexus right above the frog. When the horse puts a foot down, this dissipates concussion and the blood squishes out of it with that impact and goes back up the leg. It's a brilliant mul- tipurpose structure. Thus, a horse with a healthy frog won't be stocking up as much, and the feet and legs are healthier. It affects the whole body." Protection A healthy frog helps shield the sensitive digital cushion (the soft tissue beneath the sole that separates the frog and heel bulb from the underlying tendons and bones) and the deep digital flexor tendon above it. "Then there's the bursa and the navicular bone itself," says Burns. "There are vital structures just beneath that bottom surface. Once people realize that, they understand the impor- tance of the frog." Coordination Because the horse's heel has sensory nerve endings, the frog likely has a role with proprioception (a horse's awareness of where his feet and body are), with sensitivity a bit like the nerves at the ends of our fingertips, says Rucker. "How the horse actually puts the foot down may be partly due to the frog— feeling the ground (conditions) in regard to how it will land," she says, a concept researchers are currently studying. Traction The frog also provides trac- tion on various surfaces. We see this in snowy and icy conditions, when barefoot STEP BY STEP HEATHER SMITH THOMAS TheHorse.com/Step-By-Step The Flourishing Frog JENNAY HITESMAN This highly adaptable structure is crucial to hoof health That triangle of tissue on the bottom of your horse's foot pro- vides shock absorption, traction, protection, and more.